Short-bite aminobis(phosphonite) containing olefinic functionalities, PhN{P(OC6H3(OMe-o)(C3H5-p)) 2}2: Synthesis and transition metal complexes

Article abstract of DOI:10.1016/j.ica.2010.03.030

Short-bite aminobis(phosphonite) containing olefinic functionalities, PhN{P(OC₆H₃(OMe-o)(C₃H₅-p)) ₂}₂ (1) was synthesized by reacting PhN(PCl ₂)₂ with eugenol in the p

Full text of DOI:10.1016/j.ica.2010.03.030

Inorganica Chimica Acta 363 (2010) 3010–3016
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Short-bite aminobis(phosphonite) containing olefinic functionalities,
PhN{P(OC6H3(OMe-o)(C3H5-p))2}2: Synthesis and transition metal complexes
a
b
Maravanji S. Balakrishna a, , Susmita Naik , S.M. Mobin
*
a Phosphorus Laboratory, Department of Chemistry, Indian Institute of Technology Bombay, Mumbai 400 076, India
b National Single Crystal X-ray Diffraction Facility, Indian Institute of Technology Bombay, Mumbai 400 076, India
a r t i c l e i n f o
a b s t r a c t
Article history:
Short-bite aminobis(phosphonite) containing olefinic functionalities, PhN{P(OC6H3(OMe-o)(C3H5-p))2}2
(1) was synthesized by reacting PhN(PCl2)2 with eugenol in the presence of triethylamine. The ligand 1
Received 16 January 2010
Received in revised form 1 March 2010
Accepted 12 March 2010
Available online 18 March 2010
acts as a bidentate chelating ligand toward metal complexes [M(CO)4(C5H10NH)2] forming [M(CO)4{g2
-
PhN{P(OC6H3(OMe-o)(C3H5-p))2}2}] (M = Mo, 2; W, 3). The reaction between 1 and [CpFe(CO)2]2 leads to
the cleavage of one of the P–N bonds due to the metal assisted hydrolysis to give a mononuclear complex
[CpFe(CO){P(O)(OC6H3(OMe-o)(C3H5-p))2}{PhN(H)(P(OC6H3(OMe-o)(C3H5-p))2)}] (4). Treatment of 1 with
gold(I) derivative, [AuCl(SMe2)] resulted in the formation of a dinuclear complex, [(AuCl)2{PhN{P(O-
C6H3(OMe-o)(C3H5-p))2}2}] (5) with a AuꢀꢀꢀAu distance of 3.118(2) Å indicating the possibility of aurophilic
Dedicated to Prof. Animesh Chakravorty on
the occasion of his 75th birthday
interactions. An equimolar reaction between 1 and [Ru(
bimetallic complex [(
6-p-cymene)Ru(
structures of 1–3 and 5 were established by single crystal X-ray diffraction studies.
Ó 2010 Elsevier B.V. All rights reserved.
g
6-p-cymene)Cl2]2 afforded a tri-chloro-bridged
Keywords:
Aminobis(phosphonite)
Molybdenum, tungsten and iron complexes
Dinuclear gold(I) complex
P–N bond cleavage
g
l-Cl)3Ru{PhN(P(OC6H3(OMe-o)(C3H5-p))2)2}Cl] (6). The crystal
X-ray crystal structures
Iron–phosphorus covalent bond
1. Introduction
in catalytic reactions. Besides their catalytic utility, olefin function-
alities after phosphorus atoms are being coordinated to appropri-
ate metal centers, can participate in photochemically/thermally
induced cycloaddition reactions or olefin metathesis to produce
interesting molecules. In view of this and also as an extension of
our interest in functionalized phosphorus ligands and their metal
chemistry [6] and catalytic applications [7], we have sought to pre-
pare bisphosphine ligand system containing eugenol functional-
ities. Herein we report the synthesis and transition metal (Mo,
W, Fe, Ru and Au) chemistry of aminobis(phosphonite) appended
with eugenol substituents.
There is an upsurge interest in designing complexes containing
mixed-donor ligands or ligands with hemilabile donor functional-
ities due to their catalytic potential in various organic transforma-
tions [1]. In general, ligands containing additional donor
functionalities are ideally suited to provide temporary coordinative
saturation to the metal center through weak coordination bonds
until it is necessary to furnish an active site at the metal center
prior to the oxidative addition, an important step in homogeneous
catalysis. In these situations, poor
r-donors with p-acceptor capa-
bility are preferred so that the oxidative addition is smooth after
the metal is reduced using a base while generating an active cata-
lytic species.
2. Results and discussion
Among various mixed-donor ligands of the type P,O [2], P,N [3],
and P,S ligands [4], phosphorus and sulfur donors are especially
interesting due to the low ionization energy of sulfur and the exis-
The reaction of phenylaminobis(dichlorophosphine), PhN(PCl2)2
with eugenol in a 1:4 ratio in the presence of triethylamine and a
catalytic amount of 4-dimethylaminopyridine afforded the amin-
tence of several lone pairs of electrons besides its p-acceptor nat-
obis(diphosphonite),
PhN{P(OC6H3(OMe-o)(C3H5-p))2}2
(1)
ure, which can offer rich sulfur based coordination chemistry.
Surprisingly, phosphine derivatives containing olefin functional-
ities are sparse [5] although they are expected to play a major role
(Scheme 1). The ligand 1 is a low melting white crystalline solid
and moderately stable to air and moisture. The elucidation of the
structure of ligand 1 is based on NMR (1H and 31P{1H}) spectro-
scopic data and elemental analyses. The 31P NMR spectrum of li-
gand 1 exhibits a single resonance at 127.7 ppm. The molecular
structure of 1 is confirmed by the single crystal X-ray structure
determination.
* Corresponding author. Tel.: +91 22 2576 7181; fax: +91 22 2576 7152/2572
3480.
E-mail address: krishna@chem.iitb.ac.in (M.S. Balakrishna).
0020-1693/$ - see front matter Ó 2010 Elsevier B.V. All rights reserved.
doi:10.1016/j.ica.2010.03.030

M.S. Balakrishna et al. / Inorganica Chimica Acta 363 (2010) 3010–3016
3011
OH
OMe
Et3N,Et2 O,0o
C
+
R
R
24h
Cl
Cl
N
P
P
N
P
P
R
R
Cl
Cl
(1)
R=OC6H4(OMe-o)(C3H5 -p)
Scheme 1.
The reaction of 1 with one equivalent of M(CO)4(C5H10NH)2
(M = Mo, W) in dichloromethane at room temperature afforded
the chelate complexes, cis-[Mo(CO)4{PhN(P(OC6H3(OMe-o)(C3H5-
p))2)2}] (2) and cis-[W(CO)4{PhN(P(OC6H3(OMe-o)(C3H5-p))2)2}]
(3), respectively in moderate yields as shown in Scheme 2. The IR
spectrum of both the complexes 2 and 3 show four bands in the
carbonyl region in the range of 1900–2035 cmꢁ1 as expected for
PR2
[CpFe(CO)2]2
NH
R
N
Toluene, reflux, 24 h
PR2
Fe P O
R2P
R
OC
R=OC6H4(OMe-o)(C3H5 -p) (4)
1
a {M(CO)4} moiety of C2 symmetry [8]. The 31P NMR spectrum
Scheme 3.
m
of 2 shows a single resonance at 144.1 ppm with a coordination
shift of 16.4 ppm, whereas the 31P NMR spectrum of complex 3
1
An equimolar reaction between the ligand 1 and [Ru(
ene)Cl2]2 in THF at 60 °C resulted in the formation of a tri-chloro-
bridged bimetallic complex [( -Cl)3Ru{PhN(P(O-
6-p-cymene)Ru(
g
6-p-cym-
shows a single resonance at 117 ppm with a JWP coupling of
167.4 Hz. The structures of 2 and 3 were further confirmed by sin-
gle crystal X-ray structure determination.
g
l
The reaction of 1 with [CpFe(CO)2]2 in a 1:1 ratio in toluene un-
der reflux conditions for 24 h afforded a mononuclear complex
[CpFe(CO){P(O)(OC6H3(OMe-o)(C3H5-p))2}{PhN(H)(P(OC6H3(OMe-
o)(C3H5-p))2)}] (4) (Scheme 3). The complex 4 is formed as a result
of the moisture assisted cleavage of one of the P–N bonds during
complexation to give the aminophosphine and phosphineoxide
fragments which then bind to the metal center [9]. Similar reac-
tions of [CpFe(CO)2]2 with aminophosphines of the type PhN(PX2)2
(X = F [10], OPh [11]) led to the isolation of dinuclear complexes
containing PX2 and RN@PX2 fragments bridging the two metal cen-
ters with or without metal–metal bonds. The 31P NMR spectrum of
C6H3(OMe-o)(C3H5-p))2)2}Cl] (6) in which one of the ruthenium(II)
centers retains the cymene group. Similar type of tri-chloro-
bridged ruthenium complex containing an aminobis(phosphine)
was reported by us earlier [12]. The 31P NMR spectrum of complex
6 shows a single resonance at 97.4 ppm. The presence of a cymene
group on one of the ruthenium centers was confirmed by the 1H
NMR spectrum and elemental analysis. The 1H NMR spectrum of
3
6 shows two doublets at 5.21 and 5.05 ppm with a JHH coupling
of 5.5 Hz for the aromatic protons of cymene. The methyl groups
of isopropyl moiety appear as a doublet centered at 1.24 ppm with
a 3JHH coupling of 6.7 Hz. The chemical shift due to the –CH proton
appears as a septet around 2.80 ppm.
complex
4 shows two doublets centered at 126.7 ppm and
2
167.2 ppm with a JPP coupling of 120.9 Hz due to the presence
of two types of phosphorus centers. The low field resonance at
167.2 ppm is assigned to the {PhN(H)(P(OC6H3(OMe-o)(C3H5-
p))2)} unit whereas the resonance due to the covalently bound
phosphorus fragment, {P(O)(OC6H3(OMe-o)(C3H5-p))2} appears at
126.7 ppm. The presence of a sharp band in the IR spectrum
(õCO) at 1982 cmꢁ1 indicates the presence of a terminal carbonyl
group.
2.1. The crystal and molecular structures of 1–3 and 5
Perspective views of the molecular structures of compounds 1–
3 and 5 with the atom numbering schemes are shown in Figs. 1–4,
respectively. Crystal data and the details of the structure determi-
nations are given in Table 1 while the selected bond lengths and
the inter-bond angles appear in Tables 2 and 3.
The reaction of 1 with [AuCl(SMe2)] in a 1:2 molar ratio leads to
Compound 1 crystallizes in the extended confirmation with a
center of symmetry. The P1–N–P2 bond angle of 115.6(3)° is larger
than the average P–N–P bond angles (97–100°) observed in similar
systems [13]. The Structure of compound 1 shows a distorted tet-
rahedral geometry about the phosphorus centers and a planar
environment around the nitrogen center with the sum of angle
around nitrogen is 360°. The two P–N bond distances in compound
1 are exactly the same, 1.717(5) Å.
the formation of
a binuclear complex [(AuCl)2{l-PhN(P(O-
C6H3(OMe-o)(C3H5-p))2)2}] (5) with the ligand exhibiting the
bridging mode of coordination (see Scheme 4). The complex is sol-
uble in solvents such as CH2Cl2 and CHCl3 and is moderately stable
towards moisture and air. The 31P NMR spectrum of the complex 5
consists of a single peak at 111.2 ppm. Further evidence for the
structural composition of the complex comes from the elemental
analyses, 1H NMR data and single crystal X-ray diffraction study.
The unit cell of both the complexes 2 and 3 contain two inde-
pendent molecules with very similar bonding parameters. The
crystal structures of 2 and 3 reveal typical octahedral environ-
ments around the molybdenum and tungsten centers surrounded
by four carbonyl groups and two phosphorus centers. The two P–
N bond distances in both the complexes are slightly different in
contrast and shorter as compared to those in the free ligand,
whereas the P–O bond distances decreases by a significant amount
of 0.5–0.6 Å. The P–N–P bond angles shrink to 100.70(11)° in com-
plex 2 and 100.52(13)° in complex 3 by ꢂ15° when compared to
the same in the free ligand [115.6(3)°] due to the formation of
R2
CO
PR2
PR2
P
CO
CO
[M(pip)2(CO)4]
CH2Cl2, RT, 4 h
N
M
N
P
CO
R2
1
R=OC6H4(OMe-o)(C3H5 -p)
M= Mo (2), M = W (3)
strained four-membered chelate rings. The sum of the angles
P
Scheme 2.
around the nitrogen center ( N 359.9°) in both the complexes 2

3012
M.S. Balakrishna et al. / Inorganica Chimica Acta 363 (2010) 3010–3016
R2P Au Cl
AuCl(SMe2)
N
Au Cl
R2P
CH2Cl2, RT, 4 h
PR2
PR2
5
N
R2
Cl
P
1
[Ru
Cl2
(p-
Cy
m)]2
Cl
N
Ru
Ru
R=OC6H3(OMe-o)(C3H5 -p)
THF, 60 oC, 4 h
Cl
Cl
P
R2
6
Scheme 4.
[P1–Au1–Cl1 = 169.27 (4)° and P2–Au2–Cl2 = 175.59(4) °]. The in-
tra molecular AuꢀꢀꢀAu distance is 3.118(2) Å, which falls in the
range of the AuꢀꢀꢀAu distance considered to exhibit aurophilic inter-
actions. In spite of increase in the P–N–P bond angle in complex 5,
which on the other hand results in the increase of PꢀꢀꢀP distance
(2.943 Å) compared to the same in the free ligand 1 (2.906 Å),
the short AuꢀꢀꢀAu distance is a result of attractive interaction be-
tween the two gold centers and just an approach imposed by the
ligand. There is a slight twisting about the AuꢀꢀꢀAu vector as re-
flected by the Cl1–Au1ꢀꢀꢀAu2–Cl2 torsion angle of 11.13°. There is
no significant difference in the Au–P (Au1–P1, 2.203(1) Å; Au2–
P2, 2.193(1) Å) and Au–Cl (Au1–Cl1, 2.280(1) Å; Au2–Cl2,
2.273(1) Å) bond distances.
3. Conclusions
The aminobis(phosphonite) 1 containing olefinic functionalities
on phosphorus substituents reacts with molybdenum and tungsten
carbonyl derivatives to give the corresponding tetracarbonyl che-
late complexes in good yield. The reaction of 1 with [CpFe(CO)2]2
leads to the cleavage of one of the P–N bonds to give a FeII complex
containing protonated aminophosphine and phosphineoxide frag-
Fig. 1. Molecular structure of 1. All hydrogen atoms have been omitted for clarity.
and 3 clearly indicate the planar geometry around the bridging
nitrogen atoms. The non-bonded PꢀꢀꢀP distance in complex 2
[2.631 Å] and 3 [2.629 Å] are shorter than that in free ligand 1
[2.906 Å] which is expected due to the chelation.
The X-ray quality crystals are obtained from a mixture of
dichloromethane and petroleum ether. The gold complex crystal-
lizes in monoclinic crystal system with space group P21/c. The crys-
tal structure of complex 5 reveals that, the P–N–P bond angle
(123.68(19)°) is significantly larger compared to that of the free li-
gand (115.6(3)°). The coordination at each gold atom is only
approximately linear, as evidenced by the P–Au–Cl bond angle
ments with later making a Fe–P
r-bond. Since the crystal struc-
tures have shown the presence of olefinic functionalities on
adjacent groups in close proximity, it is possible to activate the
aromatic substituted olefins to either participate in coordination
to the metal centers or to undergo typical metathesis/cycloaddi-
tion reactions to form interesting molecules. The research works
in this direction and also to understand the behavior of P–N bonds
under various reaction conditions and in the catalytic reactions are
under active investigation in our laboratory.
Fig. 2. Molecular structure of 2. All hydrogen atoms have been omitted for clarity.

M.S. Balakrishna et al. / Inorganica Chimica Acta 363 (2010) 3010–3016
3013
Fig. 3. Molecular structure of 3. All hydrogen atoms have been omitted for clarity.
4. Experimental
4.1. General consideration
All experimental manipulations were performed under an inert
atmosphere of dry nitrogen or argon, using standard Schlenk tech-
niques. All the solvents were purified by conventional procedures
and distilled prior to use. PhN(PCl2)2 [14], M(CO)4(C5H10NH)2
(M = Mo, W) [15], [Ru(g
6-cymene)Cl2]2 [16], [AuCl(SMe2)] [17]
were prepared according to the published procedures. Other re-
agents were obtained from commercial sources and used after
purification. The 1H and 31P{1H} NMR (d in ppm) spectra were ob-
tained on a Varian VRX 400 spectrometer operating at frequencies
of 400 and 162 MHz, respectively. The spectra were recorded in
CDCl3 (or DMSO-d6) solutions with CDCl3 (or DMSO-d6) as an inter-
nal lock; TMS and 85% H3PO4 were used as internal and external
Fig. 4. Molecular structure of 5. All hydrogen atoms have been omitted for clarity.
Table 1
Crystallographic information for compound 1, 2, 3 and 5.
1
2
3
5
Empirical formula
Formula weight
Crystal system
Space group
a (Å)
C
46H49NO8P2
C50H49NO12P2Mo
1013.78
C50H49NO12P2W
1101.69
C46H49Au2Cl2NO8P2
1270.64
monoclinic
P21/c
14.7807(3)
18.6060(3)
18.5094(3)
90
111.625(2)
90
4732.02(14)
4
805.8
triclinic
P1
triclinic
triclinic
ꢀ
ꢀ
ꢀ
P1
P1
11.014(18)
11.36(2)
18.69(3)
93.06(15)
92.53(14)
113.07(16)
2142(6)
2
10.9147(10)
19.2977(6)
23.2768(12)
96.959(4)
99.514(6)
95.347(5)
4767.5(5)
4
10.9229(10)
19.3001(2)
23.2524(2)
96.9510(10)
99.9040(10)
95.4330(10)
4759.81(8)
4
b (Å)
c (Å)
a
(°)
b (°)
c
(°)
V (Å3)
Z
qcalc (Mg mꢁ3
)
1.249
0.155
1.412
0.406
1.537
2.558
1.784
6.426
l
(Mo K
a
) (mmꢁ1
)
F(0 0 0)
852
2096
2224
2472
Crystal size (mm)
T (K)
0.32 ꢃ 0.28 ꢃ 0.22
0.33 ꢃ 0.26 ꢃ 0.21
0.23 ꢃ 0.17 ꢃ 0.13
0.33 ꢃ 0.28 ꢃ 0.23
120(2)
120(2)
120(2)
120(2)
2h Range (°)
Total number of reflections
3.05–25.00
16 933
2.97–25.00
44 596
2.97–25.00
39 932
3.04–25.00
38 947
Number of independent reflections
7431
16 685
16 655
8316
[Rint = 0.0724]
0.881
0.0911
[Rint = 0.0290]
0.876
0.0338
[Rint = 0.0246]
0.907
0.0265
[Rint = 0.0446]
0.963
0.0288
Goodness-of-fit (GOF) (F2)
a
R1
b
wR2
0.2539
0.0752
0.0616
0.0460
P
P
a
R = ||Fo| ꢁ |Fc||/ |Fo|.
P
P
Rw = {[ w(F2o ꢁ Fc2)/ w(Fo2)2]}1/2, w = 1/[
r
2(F2o)+(xP)2], where P = (Fo2 þ 2F2c )/3.
b

3014
M.S. Balakrishna et al. / Inorganica Chimica Acta 363 (2010) 3010–3016
Table 2
Selected bond distances (Å) and bond angles (°) for complexes 1 and 2.
Complex 1
Complex 2
P1–N1
P2–N1
P1–O1
P1–O3
P2–O5
P2–O7
1.717(5)
1.717(5)
2.203(11)
2.193(1)
2.280(1)
2.273(1)
P1–N1–P2
O1–P1–O3
O1–P1–N1
O3–P1–N1
O5–P2–O7
O5–P2–N1
O7–P2–N1
115.6(3)
97.0(2)
100.6(3)
98.3(2)
96.9(2)
100.3(2)
97.5(2)
P1–N1
P2–N1
P1–O1
P1–O3
P2–O5
P2–O7
Mo–P1
Mo–P2
Mo–C1
Mo–C2
Mo–C3
Mo–C4
1.705(2)
1.712(2)
1.618(2)
1.619(2)
1.610(2)
1.618(2)
2.434(1)
2.444(1)
2.045(3)
1.991(3)
2.052(3)
2.020(3)
P1–N1–P2
N1–P1–Mo1
N1–P2–Mo1
O1–P1–O3
O1–P1–N1
O3–P1–N1
O5–P2–O7
O5–P2–N1
O7–P2–N1
P1–Mo–P2
100.70(11)
97.28(7)
96.72(7)
92.45(9)
103.51(10)
104.60(10)
95.12(10)
102.59(9)
103.60(10)
65.29(2)
Table 3
Selected bond distances (Å) and bond angles (°) for complexes 3 and 5.
Complex 3
Complex 5
P1–N1
P2–N1
P1–O1
P1–O3
P2–O5
P2–O7
W–P1
W–P2
W–C1
W–C2
W–C3
W–C4
1.706(2)
1.712(2)
1.613(2)
1.620(2)
1.606(2)
1.616(2)
2.425(1)
2.440(1)
2.042(4)
2.005(4)
2.050(4)
2.012(3)
P1–N1–P2
N1–P1–W1
N1–P2–W1
O1–P1–O3
O1–P1–N1
O3–P1–N1
O5–P2–O7
O5–P2–N1
O7–P2–N1
P1–W–P2
100.52(13)
97.39(8)
96.68(9)
92.53(12)
103.97(12)
104.98(12)
95.12(12)
102.86(12)
104.12(12)
65.40(2)
P1–N1
P2–N1
P1–O1
P1–O3
P2–O5
P2–O7
Au1–P1
Au2–P2
Au1–Au2
Au1–Cl1
Au2–Cl2
1.680(3)
1.670(3)
1.579(3)
1.599(3)
1.595(3)
1.581(3)
2.203(1)
2.193(1)
3.118(2)
2.280(1)
2.273(1)
P1–N1–P2
123.68(19)
169.27(4)
175.59(4)
85.24(3)
105.08(3)
90.46(3)
P1–Au1–Cl1
P2–Au2–Cl2
P1–Au1–Au2
Cl1–Au1–Au2
P2–Au2–Au1
Cl2–Au2–Au1
O1–P1–O3
O1–P1–N1
O3–P1–N1
O5–P2–O7
93.95(3)
100.18(16)
98.85(15)
101.58(16)
99.99(15)
103.72(15)
100.76(16)
O5–P2–N1
O7–P2–N1
standards for 1H and 31P{1H} NMR, respectively. Positive values
indicate downfield shifts. Microanalyses were carried out on a Car-
lo Erba (model 1106) elemental analyzer. Melting points of all
compounds were determined on a Veego melting point apparatus
and are uncorrected.
ether and kept for slow evaporation at room temperature to get
colorless crystals suitable for X-ray analysis. Yield 54%. Mp:
135 °C (decomp). Anal. Calc. for C50H49NP2O12Mo: C, 59.24; H,
4.87; N, 1.38. Found: C, 59.38; H, 4.96; N, 1.37%. 31P{1H}NMR
(CDCl3) d: 144.1(s). 1H NMR (CDCl3) d:, 3.63 (s, OCH3, 12H), 3.31
3
(d, CH2, 8H, JHH = 6.4 Hz), 5.056 (m, CH2, 8H), 5.88–5.96 (m. CH,
3
4H), 6.6 (m, C6H3, 4H), 6.95 (d, C6H3, 4H, JHH = 7.94 Hz), 6.67 (s,
4.2. Synthesis of PhN{P(OC6H3(OMe-o)(C3H5-p))2}2 (1)
C6H3, 4H), 7.32–7.57 (m, C6H5, 5H). IR (nujol or KBr disk) mCO
:
1914, 1934, 2033 cmꢁ1
.
A mixture of eugenol (10.5 g, 0.064 mol) and triethylamine
(6.98 g, 0.069 mol) in diethyl ether (10 mL) was added dropwise
to
a
solution of phenylaminobis(dichlorophosphine) (4.74 g,
4.4. Synthesis of [W(CO)4{PhN(P(OC6H3(OMe-o)(C3H5-p))2)2}] (3)
0.016 mol) in diethyl ether (30 mL) at 0 °C. The reaction mixture
was stirred at room temperature for overnight and Et3NꢀHCl was
separated by filtration through celite. The solvent was evaporated
from the filtrate under vacuum to give an oily residue. The residue
was dissolved in hot petroleum ether (bp: 60–80 °C) and kept at
room temperature for crystalisation to give analytically pure prod-
uct of 1 as colorless crystals. Yield: 73% (9.5 g). Mp: 60–62 °C. Anal.
Calc. for C46H49NO8P2: C, 68.56; H, 6.13; N, 1.74. Found: C, 68.65; H,
6.23; N, 1.70%. 31P{1H}NMR (CDCl3) d: 127.7(s). 1H NMR (CDCl3) d:
3.63 (s, OCH3, 12H), 3.31 (d, CH2, 8H, 3JHH = 6.4 Hz), 5.056 (m, CH2,
8H), 5.88–5.96 (m. CH, 4H), 6.6 (m, C6H3, 4H), 6.95 (d, C6H3, 4H,
3JHH = 7.94 Hz), 6.67 (s, C6H3, 4H), 7.32–7.57 (m, C6H5, 5H).
A solution of [W(CO)4(C5H10NH)2] (0.037 g, 0.079 mmol) in
dichloromethane (5 mL) was added dropwise to a solution of 1
(0.064 g, 0.079 mmol) in the same solvent (5 mL) with constant
stirring. The yellow colored reaction mixture was stirred for 12 h
at room temperature and filtered through a frit. The solvent was
removed under vacuum and the residue was washed with petro-
leum ether (bp: 60–80 °C) to give pale yellow colored powder of
3. The solid residue was dissolved in dichloromethane and layered
with petroleum ether and kept for slow evaporation at room tem-
perature to get colorless crystals suitable for X-ray analysis. Yield
46%. Mp: 178 °C (decomp). Anal. Calc. for C50H49NP2O12W: C,
54.51; H, 4.48; N, 1.27. Found: C, 54.78; H, 4.46; N, 1.23%.
1
31P{1H} NMR (CDCl3) d: 117.0 (s, JWP = 167.4 Hz). 1H NMR (CDCl3)
4.3. Synthesis of [Mo(CO)4{PhN{P(OC6H3(OMe-o)(C3H5-p))2}2}] (2)
3
d: 3.63 (s, OCH3, 12H), 3.31 (d, CH2, 8H, JHH = 6.4 Hz), 5.056 (m,
CH2, 8H), 5.88–5.96 (m. CH, 4H), 6.6 (m, C6H3, 4H), 6.95 (d, C6H3,
A solution of [Mo(CO)4(C5H10NH)2] (0.042 g, 0.085 mmol) in
dichloromethane (5 mL) was added dropwise to a solution of 1
(0.069 g, 0.085 mmol) also in dichloromethane (5 mL) with con-
stant stirring. The pale yellow colored reaction mixture was stirred
for 12 h at room temperature and filtered through a frit. The sol-
vent was removed under vacuum and the residue was washed with
petroleum ether to give pale yellow colored solid product of 2,
which was dissolved in dichloromethane, layered with petroleum
3
4H, JHH = 7.94 Hz), 6.67 (s, C6H3, 4H), 7.32–7.57 (m, C6H5, 5H). IR
(nujol or KBr disk) m .
CO: 1904, 1924, 2030 cmꢁ1
4.5. Synthesis of [CpFe(CO){P(O)(OC6H3(OMe-o)(C3H5-p)] (4)
A mixture of compound 1 (0.068 g, 0.084 mmol) and [CpFe(-
CO)2]2 (0.03 g, 0.084 mmol) in toluene (10 mL) was refluxed for

M.S. Balakrishna et al. / Inorganica Chimica Acta 363 (2010) 3010–3016
3015
24 h to give a dark brown solution. The reaction mixture was fil-
tered and the solvent was removed under reduced pressure to give
a dark brown crystalline solid. The residue was washed with petro-
leum ether and dried under vacuum to get dark brown solid prod-
uct of 4. Yield 94%. Mp: 98–102 °C. Anal. Calc. for C52H54NP2O6Fe: C,
68. 87; H, 6.00; N, 1.54. Found: C, 68.52; H, 5.92; N, 1.50%. 31P {1H}
NMR (CDCl3) d: 123.6 (d, 2JPP = 120.9 Hz), 167.2 (d, 2JPP = 120.9 Hz).
1H NMR (CDCl3) d:, 3.79 (s, OCH3, 12H), 3.68 (d, CH2, 8H,
3JHH = 6.4 Hz), 4.92–4.99 (m, CH2, 8H), 5.90–5.96 (m. CH, 4H),
tained free of charge from The Cambridge Crystallographic Data
Centre via www.ccdc.cam.ac.uk/data_request/cif.
Acknowledgements
We are grateful to the Department of Science and Technology
(DST), New Delhi, for financial support of this work through Grant
SR/S1/IC-02/007. S.N. thanks CSIR, New Delhi for Junior Research
Fellowship (JRF). We also thank the Department of Chemistry
Instrumentation Facilities and National Single Crystal X-ray Dif-
fraction Facility, IIT Bombay, for spectral, analytical data and X-
ray structure determination.
6.5–7.4 (m, Ph, 21H). IR (nujol or KBr disk): m .
CO: 1982 cmꢁ1
4.6. Synthesis of [(AuCl)2{PhN{P(OC6H3(OMe-o)(C3H5-p))2}2}] (5)
A solution of AuCl(SMe2) (0.03 g, 0.1 mmol) in dichloromethane
(5 mL) was added drop wise to a solution of 1 (0.041 g, 0.05 mmol)
in dichloromethane (5 mL) with constant stirring. The reaction
mixture was allowed to stir for 4 h, which was then concentrated
to 2 mL, layered with petroleum ether, and cooled to ꢁ20 °C to give
analytically pure white crystals of 5. Yield 76% Mp: 141–142 °C.
Anal. Calc. for C46H49NO8P2Au2Cl2: C, 43.48; H, 3.88; N, 1.10.
Found: C, 43.37; H, 3.79; N, 1.13%. 31P{1H}NMR (CDCl3) d:
111.2(s). 1H NMR (CDCl3) d:, 3.63 (s, OCH3, 12H), 3.31 (d, CH2,
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3016
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